I recently took my GMAT. I faired decently in Quant, but verbal has really been killing it for me. Although spoken english is not a problem, but evidently, I am not the strongest when it comes to written english, specially grammar. I need some suggestion/ guidance as to how can I improve on verbal. I prepared for SC from Manhattan. I used Kaplan for CR and RC. Should I seek professional help? or are there any other books I may refer to just to improve?